Peretó Juli, López-García Purificación, Moreira David
Unité d'Ecologie, Systématique et Evolution, UMR CNRS 8079, Université Paris-Sud, Orsay, Cedex, 91405, France.
J Mol Evol. 2005 Jul;61(1):65-74. doi: 10.1007/s00239-004-0280-8. Epub 2005 Jun 16.
Eukaryotic thiolases are essential enzymes located in three different compartments (peroxisome, mitochondrion, and cytosol) that can display catabolic or anabolic functions. They are responsible for the thiolytic cleavage of oxidized acyl-CoA (thiolase I; EC 2.3.1.16) and the synthesis or degradation of acetoacetyl-CoA (thiolase II; EC 2.3.1.9). Phylogenetic analysis of eukaryotic thiolase sequences showed that they form six distinct clusters, one of them highly divergent, which are in good correlation with their class and subcellular location. When analyzed together with a representative sample of prokaryotic thiolases, all eukaryotic thiolase groups emerged close to proteobacterial sequences. Metazoan cytosolic thiolase II was related to alpha-proteobacterial sequences, suggesting a mitochondrial origin. Unexpectedly, cytosolic thiolases from green plants and fungi as well as at least one member of all eukaryotic peroxisomal and mitochondrial thiolases had delta-proteobacteria as closest relatives. Our analysis suggests that these eukaryotic peroxisomal and mitochondrial thiolases may have been acquired from delta-proteobacteria prior to the ancestor of all known eukaryotes.
真核硫解酶是位于三个不同区室（过氧化物酶体、线粒体和细胞质）的必需酶，可发挥分解代谢或合成代谢功能。它们负责氧化型酰基辅酶A的硫解裂解（硫解酶I；EC 2.3.1.16）以及乙酰乙酰辅酶A（硫解酶II；EC 2.3.1.9）的合成或降解。对真核硫解酶序列的系统发育分析表明，它们形成六个不同的簇，其中一个高度分化，这与它们的类别和亚细胞定位密切相关。当与原核硫解酶的代表性样本一起分析时，所有真核硫解酶组都出现在靠近变形菌序列的位置。后生动物细胞质硫解酶II与α-变形菌序列相关，表明其起源于线粒体。出乎意料的是，绿色植物和真菌的细胞质硫解酶以及所有真核过氧化物酶体和线粒体硫解酶中的至少一个成员与δ-变形菌是最近的亲属。我们的分析表明，这些真核过氧化物酶体和线粒体硫解酶可能在所有已知真核生物的祖先之前就已从δ-变形菌中获得。
